One-Step Microfluidic Fabrication of Bioinspired Microfibers with a Spindle-Knot Structure for Fog Harvest

Many biomimetic microfibers have been designed from spider silk to collect water efficiently from humid air as a result of its periodic spindle-knot structure, which enhances the direct movement and convergence of captured fog droplets. Here, a hydrodynamic flow-focusing microfluidic device with a theta-shaped tube is designed for the one-step fabrication of bioinspired microfibers with a spindle-knot structure for fog harvest. The morphology of the structured microfibers, including height, width, and spacing of spindle knots, can be adjusted readily by regulating the flow rate of specific phases. The production rate of these structured microfibers can reach 1100 cm/min. Moreover, the capture, transportation, and collection performance of fog droplets on various microfibers are investigated in a fog collection platform. It is demonstrated that our one-step microfluidic device presents a ready method for the fabrication of structured microfibers with spindle knots, which provide a significant facilitation on efficient fog capture and water collection.